Jay P. Dunn

Augusta State University, Augusta, Georgia, United States

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Publications (14)56.07 Total impact

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    ABSTRACT: We present a study of Broad Absorption Line (BAL) quasar outflows that show S IV ?1063 and S IV* ?1073 troughs. The fractional abundance of S IV and C IV peak at similar value of the ionization parameter, implying that they arise from the same physical component of the outflow. Detection of the S IV* troughs will allow us to determine the distance to this gas with higher resolution and higher signal-to-noise spectra, therefore providing the distance and energetics of the ubiquitous C IV BAL outflows. In our bright sample of 156 SDSS quasars 14% show C IV and 1.9% S IV troughs, which is consistent with a fainter magnitude sample with twice as many objects. One object in the fainter sample shows evidence of a broad S IV trough without any significant trough present from the excited state line, which implies that this outflow could be at a distance of several kpc. Given the fractions of C IV and S IV, we establish firm limits on the global covering factor on S IV that ranges from 2.8% to 21% (allowing for the k-correction). Comparison of the expected optical depth for these ions with their detected percentage suggests that these species arise from common outflows with a covering factor closer to the latter.
    The Astrophysical Journal 06/2012; 750(2). · 6.73 Impact Factor
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    ABSTRACT: We present absorption line analysis of the outflow in the quasar IRAS F04250–5718. Far-ultraviolet data from the Cosmic Origins Spectrograph on board the Hubble Space Telescope reveal intrinsic narrow absorption lines from high ionization ions (e.g., C IV, N V, and O VI) as well as low ionization ions (e.g., C II and Si III). We identify three kinematic components with central velocities ranging from ~–50 to ~–230 km s–1. Velocity-dependent, non-black saturation is evident from the line profiles of the high ionization ions. From the non-detection of absorption from a metastable level of C II, we are able to determine that the electron number density in the main component of the outflow is 30 cm–3. Photoionization analysis yields an ionization parameter log U H ~ –1.6 ± 0.2, which accounts for changes in the metallicity of the outflow and the shape of the incident spectrum. We also consider solutions with two ionization parameters. If the ionization structure of the outflow is due to photoionization by the active galactic nucleus, we determine that the distance to this component from the central source is 3 kpc. Due to the large distance determined for the main kinematic component, we discuss the possibility that this outflow is part of a galactic wind.
    The Astrophysical Journal 08/2011; 739(1):7. · 6.73 Impact Factor
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    ABSTRACT: We present absorption line analysis of the outflow in the quasar IRAS F04250-5718. Far-ultraviolet data from the Cosmic Origins Spectrograph onboard the Hubble Space Telescope reveal intrinsic narrow absorption lines from high ionization ions (e.g., C IV, N V, and O VI) as well as low ionization ions (e.g., C II and Si III). We identify three kinematic components with central velocities ranging from ~-50 to ~-230 km/s. Velocity dependent, non-black saturation is evident from the line profiles of the high ionization ions. From the non-detection of absorption from a metastable level of C II, we are able to determine that the electron number density in the main component of the outflow is < 30 per cubic cm. Photoionization analysis yields an ionization parameter log U ~ -1.6 +/- 0.2, which accounts for changes in the metallicity of the outflow and the shape of the incident spectrum. We also consider solutions with two ionization parameters. If the ionization structure of the outflow is due to photoionization by the active galactic nucleus, we determine that the distance to this component from the central source is > 3 kpc. Due to the large distance determined for the main kinematic component, we discuss the possibility that this outflow is part of a galactic wind.
    06/2011;
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    ABSTRACT: We present Subaru observations of the newly discovered luminous quasar AKARI J1757+5907, which shows an absorption outflow in its spectrum. The absorption consists of 9 distinct troughs, and our analysis focuses on the troughs at ~ -1000$ km s^{-1} for which we can measure accurate column densities of He I*, Fe II and Mg II. We use photoionization models to constrain the ionization parameter, total hydrogen column density, and the number density of the outflowing gas. These constraints yield lower limits for the distance, mass flow rate and kinetic luminosity for the outflow of 3.7 kpc, 70 M_{sun} yr^{-1}, and 2.0 x 10^{43} ergs s^{-1}, respectively. Such mass flow rate value can contribute significantly to the metal enrichment of the intra-cluster medium. We find that this moderate velocity outflow is similar to those recently discovered in massive post-starburst galaxies. Finally, we describe the scientific potential of future observations targeting this object.
    Publications- Astronomical Society of Japan 01/2011; 63. · 2.44 Impact Factor
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    Manuel A. Bautista, Jay P. Dunn
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    ABSTRACT: We show that time variations in the UV ionizing continuum of quasars, on scales of $\sim$1 year, affect the dynamic structure of the plasmas responsible for low ionization broad absorption lines. Variations of the ionizing continuum produce non-equilibrium photoionization conditions over a significant fraction of the absorbing clouds and supersonically moving ionization fronts. When the flux drops the contraction of the ionized region drives a supersonic cooling front towards the radiation source and a rarefaction wave in the opposite direction. The pressure imbalance is compensated by an increased speed of the cool gas relative to the front. When the flux recovers the cool gas is re-ionized and re-heated by a supersonic ionization front traveling away from the radiation source and a forward shock is created. The reheated clouds equilibrate to a temperature of $\sim 10^4$ K and are observed to have different radial velocities than the main cloud. Such fragmentation seems consistent with the multicomponent structure of troughs seen in some objects. The velocity differences measured among various components in the quasars QSO 2359--1241 and SDSS J0318--0600 can be reproduced by our model if strong magnetic fields ($\sim$10 mG) are present within the clouds. Comment: 2 figure, accepted for publication in ApJ Letters
    The Astrophysical Journal Letters 06/2010; · 6.35 Impact Factor
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    ABSTRACT: We present the ultraviolet (UV) and X-ray spectra observed with the Far Ultraviolet Spectroscopic Explorer (FUSE) and the XMM-Newton satellite, respectively, of the low-z Seyfert 1 galaxy IRAS F22456 – 5125. This object shows absorption from five distinct, narrow kinematic components that span a significant range in velocity (~0 to –700 km s–1) and ionization (Lyman series, C III, N III, and O VI). We also show that three of the five kinematic components in these lines appear to be saturated in Lyβ λ1026 and that all five components show evidence of saturation in the O VI doublet lines λλ1032, 1038. Further, all five components show evidence for partial covering due to the absorption seen in the O VI doublet. This object is peculiar because it shows no evidence for corresponding X-ray absorption to the UV absorption in the X-ray spectrum, which violates the 1:1 correlation known for low-z active galactic nuclei (AGNs). We perform photoionization modeling of the UV absorption lines and predict that the O VII column density should be small, which would produce little to no absorption in agreement with the X-ray observation. We also examine the UV variability of the continuum flux for this object (an increase of a factor of 6). As the absorption components lack variability, we find a lower limit of ~20 kpc for the distance for the absorbers from the central AGN.
    The Astrophysical Journal 03/2010; 713(2):900. · 6.73 Impact Factor
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    ABSTRACT: Using high-resolution Very Large Telescope spectra, we study the multi-component outflow systems of two quasars exhibiting intrinsic Fe II absorption (QSO 2359-1241 and SDSS J0318-0600). From the extracted ionic column densities and using photoionization modeling, we determine the gas density, total column density, and ionization parameter for several of the components. For each object, the largest column density component is also the densest, and all other components have densities of roughly 1/4 of that of the main component. We demonstrate that all the absorbers lie roughly at the same distance from the source. Further, we calculate the total kinetic luminosities and mass outflow rates of all components and show that these quantities are dominated by the main absorption component.
    The Astrophysical Journal 03/2010; 713(1):25. · 6.73 Impact Factor
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    ABSTRACT: We search a sample of 123 high redshift quasars (z>2.9), observed by the Sloan Digital Sky Survey, in order to determine the frequency that objects contain outflow absorption troughs in their spectra from the high ionization resonance line of S IV (lambda1063) and the metastable, excited line S IV* (lambda1073). Of the 123 quasars, we find that 25 contain C IV Broad absorption Lines (BALs) and 4 objects with absorption from S IV and S IV* that cannot be due to Lyman alpha forest contamination due to their velocity widths (Deltav>500 km/s) and excellent agreement between the S IV and S IV* trough profiles as well as those of other ions (e.g., C IV, N V, and Si IV). Thus, the fraction of quasars in our sample with C IV BALs is 0.20, and the fraction with S IV and S IV* absorption is 0.03, which provides a lower limit to the global covering of these outflows. Furthermore, we evaluate the expected frequency of S IV absorption in C IV absorption systems, and find that the observed detection rate is consistent with a similar global covering for the two ions.
    01/2010;
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    ABSTRACT: We present high spectral resolution VLT observations of the BAL quasar SDSS J0318-0600. This high quality data set allows us to extract accurate ionic column densities and determine an electron number density of n_e=10^3.3 +/- 0.2 cm^-3 for the main outflow absorption component. The heavily reddened spectrum of SDSS J0318-0600 requires purely silicate dust with a reddening curve characteristic of predominately large grains, from which we estimate the bolometric luminosity. We carry out photoionization modeling to determine the total column density, ionization parameter and distance of the gas and find that the photionization models suggest abundances greater than solar. Due to the uncertainty in the location of the dust extinction, we arrive at two viable distances for the main ouflow component from the central source, 6 and 18 kpc, where we consider the 6 kpc location as somewhat more physically plausable. Assuming the canonical global covering of 20% for the outflow and a distance of 6 kpc, our analysis yields a mass flux of 120 M_sun yr^-1 and a kinetic luminosity that is ~0.1% of the bolometric luminosity of the object. Should the dust be part of the outflow, then these values are ~4x larger. The large mass flux and kinetic luminosity make this outflow a significant contributor to AGN feedback processes. Comment: Accepted for publication in ApJ, 57 pages, 14 figures
    The Astrophysical Journal 11/2009; · 6.73 Impact Factor
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    ABSTRACT: We present high spectral resolution, high signal-to-noise Very Large Telescope (VLT) data of the QSO SDSSJ0318-0600 (z=1.967), along with the measured quantities pertaining to the outflow absorption seen in both high and low ionization species. SDSSJ0318-0600 shows an array of 11 separable kinematic components in blueshifted absorption spanning a velocity range of -2800 to -7500 km/s. Our column density analysis provides ratios to determine electron densities, total hydrogen column densities, and distances for three of the components, the fastest (-7500 km/s), slowest (-2800 km/s) and strongest (-4200 km/s) components of the outflows. Provided these quantities for the absorber with the largest hydrogen column density, we find kinetic luminosity, mass flux, and abundances. These results provide an example of an AGN wind that could account for enough energy to suppress cooling flows in clusters, supply enough metals to account for a small fraction of ICM metallicity, and affect the rate of super massive black hole growth.
    01/2009;
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    ABSTRACT: In a continuing survey of active galactic nuclei observed by the Far Ultraviolet Spectroscopic Explorer, we provide a deeper analysis of intrinsic absorption features found in 35 objects. Our survey is for low-redshift and moderate-luminosity objects, mostly Seyfert galaxies. We find a strong correlation between maximum radial velocity and luminosity. We also examine the relationships between equivalent width (EW), full width at half maximum, velocity: and continuum flux. The correlation between velocity and luminosity has been explored previously by Laor & Brandt, but at a significantly higher redshift and heavily weighted by broad absorption line quasars. We also have examined each object with multiple observations for variability in each of the aforementioned quantities, and have characterized the variation of EW with the continuum flux. In our survey, we find that variability of O VI lambda1032, lambda1038 is less common than of the UV doublets of CIV and N V seen at longer wavelengths, because the O VI absorption is usually saturated. Lyman beta absorption variability is more frequent. In a target-by-target examination we find that broad absorption line absorption and narrow absorption line absorbers are related in terms of maximum outflow velocity and luminosity, and both can be exhibited in similar luminosity objects. We also find one object that shows radial velocity change, seven objects that show equivalent width variability, and two objects that show either transverse velocity changes or a change in ionization. Comment: 56 pages, 23 figures, Accepted for AJ, 2008 May 19
    The Astronomical Journal 07/2008; · 4.97 Impact Factor
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    ABSTRACT: We present a survey of 72 Seyfert galaxies and quasars observed by the it Far Ultraviolet Spectroscopic Explorer (FUSE). We have determined that 72 of 253 available active galactic nuclei (AGN) targets are viable targets for detection of intrinsic absorption lines. We examined these spectra for signs of intrinsic absorption in the O VI doublet (lambda 1031.9, 1037.6) and Lyman beta (lambda 1025.7). The fraction of Seyfert 1 galaxies and low-redshift quasars at z < 0.15 that show evidence of intrinsic UV absorption is ~50%, which is slightly lower than Crenshaw et al. (1999) found (60%) based on a smaller sample of Seyfert 1 galaxies observed with the Hubble Space Telescope (HST). With this new fraction we find a global covering factor of the absorbing gas with respect to the central nucleus of ~0.4. Our survey is to date the largest searching for intrinsic UV absorption with high spectral resolution, and is the first step toward a more comprehensive study of intrinsic absorption in low-redshift AGN.
    The Astronomical Journal 07/2007; · 4.97 Impact Factor
  • Jay P. Dunn, D. Crenshaw, S. Kraemer
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    ABSTRACT: We have obtained new spectroscopic data of the Seyfert 1 galaxy NGC 3516 via the Far Ultraviolet Spectroscopic Explorer (FUSE). This spectrum was obtained based on X-ray data that showed that the flux state of NGC 3516 was increasing. It provides us with the only high resolution spectrum of NGC 3516 in the far ultraviolet range with a significant signal to noise ratio. We provide the far UV continuum lightcurve of NGC 3516 observed by both FUSE and by the Hopkins Ultraviolet Explorer (HUT) as well as the near UV continuum lightcurve observed by the International Ultraviolet Explorer (IUE), the Faint Object Spectrograph (FOS) and the Space Telescope Imaging Spectrograph (STIS) to show the overall flux state of the galaxy. This lightcurve shows that the continuum flux state for NGC 3516 is increasing. We have fit a H2 spectrum to both the most recent spectrum and to the average spectrum for all 5 FUSE observations to obtain a measure of the column density for several different rotational states. The main focus of our work is to characterize the intrinsic absorption seen in the O IV doublet (lambdalambda 1031.9,1037.6 Å) and in the Lyman beta(lambda 1025.7 Å) absorption.
    06/2006;
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    ABSTRACT: Using the Multimission Archive at STScI (MAST), we have extracted spectra and determined continuum light curves for 175 Seyfert galaxies that have been observed with the International Ultraviolet Explorer and the Faint Object Spectrograph on the Hubble Space Telescope. To obtain the light curves as a function of Julian Date, we used fixed bins in the object's rest frame and measured small regions (between 30 and 60 Å) of each spectrum's continuum flux in the range 1150 to 3200 Å. We provide access to the UV light curves and other basic information about the observations in tabular and graphical form via the Internet at http://www.chara.gsu.edu/PEGA/IUE.
    Publications of the Astronomical Society of the Pacific 03/2006; 118:572-579. · 3.69 Impact Factor

Publication Stats

101 Citations
56.07 Total Impact Points

Institutions

  • 2011–2012
    • Augusta State University
      • Department of Chemistry and Physics
      Augusta, Georgia, United States
  • 2010
    • Virginia Polytechnic Institute and State University
      • Department of Physics
      Blacksburg, Virginia, United States
  • 2007–2008
    • Georgia State University
      • Department of Physics and Astronomy
      Atlanta, Georgia, United States
  • 2006
    • The University of Arizona
      Tucson, Arizona, United States